All Liberty Seated Half Dimes were struck in a composition of 90% silver and 10% copper with a diameter of 15.5 mm. The standard weight of the coins at the beginning of the series was 1.3 grams (20.6 grains). This standard was modified part of the way through 1853 when the weight was reduced to 1.2 grams (19 grains). The change was noted by adding arrows to each side of the date. The arrows would be removed from the design after 1855, although the modified specifications continued in use until the conclusion of the series.
During the series, coins were produced at the Philadelphia, New Orleans, and San Francisco Mint facilities. As usual, the Philadelphia minted coins have no mintmark. The coins from the other two facilities initially had the mint mark located on the reverse within the wreath, under the denomination. For the “Legend on Obverse” subtype, the mint mark was moved below the wreath, although it would be moved to the old location for the final years of the series. For certain years, both mint mark positions exist.
